JP3034130B2 - Method for producing thermoplastic polyurethane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyurethane useful as a thermoplastic elastomer having rubber-like elasticity and excellent in heat resistance and mechanical strength.

[0002]

2. Description of the Related Art Polyurethane has rubber elasticity at room temperature, and is moldable, like thermoplastic polyurethane elastomer (TPU) described in a literature (Plastic Age, May 1985, p.96, etc.). Therefore, it is widely used in various industrial products. TPU has superior abrasion resistance and mechanical strength as compared with natural rubber and synthetic rubber, but these characteristics are due to physical constraints such as hydrogen bonding of hard segment portions contained in the polymer chain of TPU. Express. On the other hand, the heat resistance is low because the softening melting point of the hard segment is restricted. In order to improve heat resistance, the content ratio of the hard segment may be increased,
In this case, the obtained molded body has increased hardness at room temperature and low temperature, and thus has reduced flexibility.

In order to solve the above problems, for example, at least one of a dihydroxy compound represented by the above general formula [I] and a monohydroxy compound represented by the above general formula [II] is used as a component. Is known. In this polyurethane, since the cohesive force of the hard segment based on the hydroxy component is very strong, it is possible to reduce the content of the hard segment, and it has excellent heat resistance and mechanical properties, and flexibility at room temperature and low temperature. This makes it possible to obtain a thermoplastic elastomer having excellent heat resistance.

[0004]

Generally, when producing a thermoplastic polyurethane, a solvent such as toluene and methyl ethyl ketone is used as described in JP-B-63-40207. However, when a highly polar compound such as the above-mentioned dihydroxy compound and monohydroxy compound is used as a monomer, the solubility of the monomer in the above-mentioned solvent is extremely poor, which is not preferable.

When a highly polar monomer is used, for example, as described in JP-A-4-46918, N, N-
Highly polar solvents such as dimethylformamide and N-methylpyrroline are used. These solvents are toxic and difficult to handle, and require a step of removing the solvent during production, which is disadvantageous in terms of energy and cost.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a thermoplastic polyurethane having rubber elasticity and excellent in heat resistance and mechanical strength, which is safe and easy to handle. Another object of the present invention is to provide a method for manufacturing with good productivity.

[0007]

The process for producing a thermoplastic polyurethane according to the present invention comprises (A) a dihydroxy compound represented by the following general formula [I] and a monohydroxy compound represented by the following general formula [II]: , At least one hydroxy compound, (B) a polyether,
(C) diisocyanate in a reactor at 60 to 300 ° C.
The bulk reaction is performed in the temperature range described above, whereby the above object is achieved.

[0008]

Embedded image

(Wherein R ¹ and R ^{2 each} independently represent an alkylene group, p is 3 or 4, and q and r each independently represent 0 or an integer of 1 or more).

[0010]

Embedded image

(Wherein, R ³ represents an alkylene group, 1 is 2 or 3, and m represents 0 or an integer of 1 or more).

Next, the present invention will be described in detail.

The hydroxy compound (A) used in the present invention is selected from at least one of a dihydroxy compound represented by the general formula [I] and a monohydroxy compound represented by the general formula [II]. .

The dihydroxy compound represented by the above general formula [I] is a low molecular compound exhibiting liquid crystallinity. In the above general formula [I], the alkylene groups R ¹ and R ² are preferably an ethylene group or a propylene group, and q and r are preferably 0 or 1. Examples of the dihydroxy compound include 4,4 '''-dihydroxy-p-quarterphenyl and 4,4'''-di (2-hydroxyethoxy) -p-quarterphenyl. They may be used or may be used in combination.

In the monohydroxy compound represented by the general formula [II], R ³ is preferably an ethylene group or a propylene group, and n is preferably 0 or 1. Examples of the monohydroxy compound include, for example, 4-hydroxy
-p-terphenyl, 4-hydroxy-p-quarterphenyl, 4- (2-hydroxyethoxy) -p-terphenyl, 4-
(2-Hydroxyethoxy) -p-quarterphenyl and the like, each of which may be used alone or in combination.

The hydroxy compounds represented by the above general formulas [I] and [II] are rigid low molecular weight compounds having a paraphenylene skeleton and have an extremely high melting point due to their characteristic molecular structure. Furthermore, the paraphenylene skeleton is known to be effective as a mesogen of a low-molecular liquid crystal compound, which means that the paraphenylene skeleton is not only in a solid state but also in a high temperature state (molten state).
It shows that it has strong cohesion. Therefore, when the hydroxy compound is incorporated into a polymer terminal or in a polymer molecule, a very strong and highly heat-resistant physical cross-link is formed in the polymer, so that a thermoplastic elastomer having excellent heat resistance can be obtained. .

The polyether (B) used in the present invention includes, for example, homopolymers and copolymers such as polyethylene oxide, polypropylene oxide, polytetramethylene oxide and polyhexamethylene oxide. These may be used alone. Or two or more of them may be used in combination. The number average molecular weight of the polyether is preferably from 100 to 20,000, more preferably from 500 to 5,000, and particularly preferably from 800 to 2,000.
5000. When the number average molecular weight is less than 100, the ability to impart flexibility to the resulting polyurethane may be reduced. When the number average molecular weight exceeds 20,000, physical properties such as thermal stability of the obtained polyurethane are obtained. May decrease.

As the diisocyanate (C) used in the present invention, any of aliphatic diisocyanate, alicyclic diisocyanate and aromatic diisocyanate can be used.

Examples of the aliphatic diisocyanate include 1,2-ethylene diisocyanate, 1,3-propylene diisocyanate, 1,4-butane diisocyanate, and
1,6-hexamethylene diisocyanate and the like.
Examples of the alicyclic dissocyanate include 1,4-cyclohexane diisocyanate and 4,4-cyclohexane diisocyanate. Further, examples of the aromatic diisocyanate include 4,4′-diphenylmethane diisocyanate, tolylene diisocyanate, and naphthalene diisocyanate.

In the case of producing a thermoplastic polyurethane comprising the dihydroxy compound [I], the polyether (B) and the diisocyanate (C), the amount of the dihydroxy compound [I] to be added constitutes the polyurethane. It is preferably from 1 to 30% by weight, more preferably from 3 to 20% by weight, particularly preferably from 5 to 15% by weight of the total monomers. When the added amount of the dihydroxy compound [I] is less than 1% by weight, the heat resistance of the obtained polyurethane may be lowered. When the added amount of the dihydroxy compound [I] exceeds 30% by weight, the elastic modulus may be reduced. It becomes high and the flexibility decreases, and the properties as a thermoplastic polyurethane may be inferior.

When a thermoplastic polyurethane comprising the above-mentioned monohydroxy compound [II], polyether (B) and diisocyanate (C) is produced, the amount of addition of the above-mentioned monohydroxy compound [II] is not limited to polyurethane. The content is preferably 1 to 30% by weight based on all the monomers constituting the polymer. If the amount of the monohydroxy compound [II] is less than 1% by weight, the heat resistance of the obtained polyurethane may be reduced. If it exceeds 30% by weight, the molecular weight of the polyurethane does not increase sufficiently. The physical properties of the thermoplastic polyurethane may be inferior.

In the case of producing a thermoplastic polyurethane comprising both the dihydroxy compound [I] and the monohydroxy compound [II], a polyether (B) and a diisocyanate (C), the dihydroxy compound [I ] And the monohydroxy compound [II] are added in an amount of 1 to 1 in all monomers constituting the polyurethane.
It is preferably 30% by weight. If the combined amount of the dihydroxy compound [I] and the monohydroxy compound [II] is less than 1% by weight, heat resistance may be reduced,
On the other hand, if it exceeds 30% by weight, the flexibility is lowered and a sufficient increase in molecular weight may not be obtained.

In this case, the addition ratio of the dihydroxy compound [I] and the monohydroxy compound [II] is preferably in a range satisfying 0 <[II] / [I] + [II] <2/3.

The thermoplastic polyurethane obtained by the production method of the present invention may contain, as a copolymer component, a polyester, a polysilicone and a polylactone having two hydroxyl groups.

Further, aromatic diols, aliphatic diols and alicyclic diols other than the above-mentioned dihydroxy compound [I] may be added as a component as a chain extender.

Examples of the aromatic diol include hydroquinone, resorcin, chlorohydroquinone, bromohydroquinone, methylhydroquinone, phenylhydroquinone, methoxyhydroquinone, phenoxyhydroquinone, 4,4'-
Dihydroxybiphenyl, 4,4'-dihydroxydiphenylether, 4,4'-dihydroxydiphenylsulfide, 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenylmethane, bisphenol A, 1, 1-di (4-hydroxyphenyl) cyclohexane, 1,2-bis (4-hydroxyphenoxy) ethane, 1,4-dihydroxynaphthalene, and
2,6-dihydroxynaphthalene and the like. Examples of the aliphatic diol include glycol and polyalkylene glycol, for example, ethylene glycol, propylene glycol, trimethylene glycol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 6-hexanediol, 1,7-heptanediol,
1,8-octanediol, 1,9-nonanediol and 1,10
-Decanediol. Further, as the alicyclic diol, cyclopentane-1,2-diol, cyclohexane-1,2-diol, cyclohexane-1,3-diol, cyclohexane-1,4-diol, and cyclohexane-1,4-diol Dimethanol and the like. These may be used alone or in combination of two or more.

The method for producing a thermoplastic polyurethane of the present invention is carried out in a bulk state without using a solvent in order to simplify the production process and save energy and cost. In this case, the manufacturing method includes the following three methods.

The three components of the hydroxy compound (A), the polyether (B) and the isocyanate (C) are added all at once to the reactor, and then a heating reaction is performed in the reactor.

[0029] The isocyanate (C) and the hydroxy compound (A) or polyether (B) are added to the reactor,
After the heat reaction in the reactor, the remaining components are added to raise the reaction temperature, and then the heat reaction is further performed.

The hydroxy compound (A) and the polyether (B) are added to a reactor, heated and melted to make a uniform state, and then the isocyanate (C) is added to carry out a heating reaction.

The above method is easy to operate, and the above method is easy to control the reaction and the structure of the polymer to be produced. Further, according to the above method, the reaction temperature can be lowered and the energy efficiency can be increased.

The reactor used in the above-mentioned production method is generally provided with a stirring blade, a raw material inlet, a nitrogen port or a decompression port, and the inner wall is made of metal such as glass or stainless steel. Kneaders and extruders, such as controllable reactors or kneaders.

The reaction temperature in the above production method is 60 to
The range is 300 ° C. When the reaction temperature is lower than 60 ° C., the reaction does not proceed because the dissolution of the hydroxy compound (A) and other components is insufficient. On the other hand, when the reaction temperature is 300 ° C
If it exceeds 30, the product is decomposed, and a polymer having sufficient strength cannot be obtained. The preferred range of the reaction temperature is 100 to 280 ° C, but the reaction temperature is preferably in the range of 200 to 260 ° C from the balance between solubility of the hydroxy compound (A) in other components and decomposability of the product. Particularly preferred. Even in these reaction temperature ranges, the reaction system is opaque and the hydroxy compound (A) does not seem to be sufficiently dissolved, but the reaction proceeds.

The reaction time in the above production method is 2 minutes to 2 minutes.
The time range is preferably, more preferably, 5 to 30 minutes, and particularly preferably, 10 to 20 minutes.
If the reaction time is less than 2 minutes, the reaction may not proceed sufficiently, while if the reaction time exceeds 2 hours, the product may be decomposed.

Further, the above reaction is preferably carried out in an inert gas such as nitrogen, argon and xenon in order to suppress decomposition of the product.

In the method for producing a thermoplastic polyurethane of the present invention, the reaction can be carried out using a catalyst. Preferred catalysts include diacyl stannous, tetraacylstannic, dibutyltin oxide, dibutyltin dilaurate, dimethyltin malate, tin dioctanoate, tin tetraacetate, stannas octoate, triethylenediamine, diethyleneamine, triethylamine, metal naphthenate Salt, metal octylate, triisobutylaluminum,
Examples include tetrabutyl titanate, calcium acetate, germanium dioxide and antimony trioxide. These catalysts may be used alone or in combination of two or more.

The following additives may be further added to the thermoplastic polyurethane obtained by the production method of the present invention as long as its practicality is not lost.

(I) Inorganic fiber: glass fiber, carbon fiber, boron fiber, silicon carbide fiber, alumina fiber, amorphous fiber, silicon / titanium / carbon fiber, etc.

(Ii) Organic fibers: aramid fibers and the like.

(Iii) Inorganic filler: calcium carbonate, titanium oxide, mica, talc and the like.

(Iv) Heat stabilizer: triphenyl phosphite, trilauryl phosphite, 2-tert-butyl-α- (3
-tert-butyl-4-hydroxyphenyl) -p-cumenylbis (p-nonylphenyl) phosphite and the like.

(V) Flame retardants: hexabromocyclododecane, tris- (2,3-dichloropropyl) phosphate,
Pentabromophenyl allyl ether and the like.

(Vi) UV absorber: p-tert-butylphenyl salicylate, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, 2,4,5-trihydroxybutyrophenone etc.

(Vii) Antioxidants: butylhydroxyanisole, butylhydroxytoluene, distearylthiodipropionate, dilaurylthiodipropionate and the like.

(Viii) Antistatic agent: N, N-bis (hydroxyethyl) alkylamine, alkylallyl sulfonate, alkyl sulfanate and the like.

(Ix) Inorganic substances: barium sulfate, alumina, silicon oxide and the like.

(X) Higher fatty acid salts: sodium stearate, barium stearate, sodium palmitate and the like.

(Xi) crystallization promoter: benzyl alcohol,
Benzophenone and the like.

Further, the polyurethane obtained by the production method of the present invention may contain other thermoplastic resins such as polyolefin,
By mixing with a modified polyolefin, polystyrene, polyamide, polycarbonate, polysulfone, polyester, or the like, or by mixing with a rubber component, the properties can be modified and used.

The thermoplastic polyurethane obtained by the production method of the present invention is formed into a molded article by a melt molding method such as press molding, extrusion molding, injection molding, and blow molding. The physical properties of the molded article can be arbitrarily changed depending on the constituent components and the mixing ratio thereof. The molded article can be suitably used for various parts requiring flexibility, such as automobile parts, hoses, belts, and packings, or paints and adhesives.

[0051]

The present invention will be described below with reference to examples and comparative examples. The polyurethanes obtained in the following Examples and Comparative Examples were evaluated based on the following methods.

<Breaking Strength and Elongation at Break> The obtained polyurethane was press-molded into a sheet having a thickness of 3 mm, and the sheet was punched into a dumbbell-shaped test piece, and then subjected to JIS K
A tensile test was performed according to 7311, and the breaking strength and the breaking elongation were measured.

<Vicat Softening Point> The obtained polyurethane was formed into a molded product having a thickness of 5 mm, 10 mm × 10 mm by press molding, and a 1 kg load was applied to the molded product to measure the softening point of the molded product.

Example 1 A polyether having a number average molecular weight of about 1000 (BASF;
PolyTHF2000) 100 g (0.1 mol)
And 34.8 g of tolylene diisocyanate (0.2 mo
l) and a small amount of dibutyltin laurylate as a catalyst, into a reaction vessel equipped with a stirring blade, a material input port, a nitrogen port or a decompression port, whose inner wall is made of stainless steel and whose temperature can be controlled in a temperature range of room temperature to 300 ° C. In addition, the mixture was reacted at 80 ° C. for 2 hours. Thereafter, 10 g (0.03 mol) of 4,4 ′ ″-dihydroxy-p-quarterphenyl and 16.0 g (0.07 mol) of bisphenol A were added and reacted at 250 ° C. for 20 minutes. As the reaction proceeded, a viscous milky white fluid was obtained. The obtained polymer had a Vicat softening point of 106 ° C., a breaking strength of 420 kgf / cm ² and a breaking elongation of 600%, and had flexibility at room temperature.

COMPARATIVE EXAMPLE 1 22.8 g (0.1 mol) of bisphenol A, 100 g of the polyether used in Example 1, and 34.8 g (0.2 mol) of tolylene diisocyanate were collectively charged with stirring blades and raw materials. An inner wall made of SUS316 provided with a mouth, a nitrogen port, or a decompression port was made of SUS 316, and the temperature was controlled in a temperature range of room temperature to 300 ° C. After this, 2
The temperature was raised to 60 ° C., and the reaction was continued for 20 minutes. The inside of the system became viscous with the reaction. Although the resulting polymer had a Vicat softening point of 32 ° C., the resulting polyurethane was hard and brittle at room temperature, so that a tensile test could not be performed.

Example 2 33.8 g of 4,4 '''-dihydroxy-p-quarterphenyl
(0.1 mol) and polyether (BASF; Po
lyTHF2000) and 50.1 g (0.2 mol) of diphenylmethane diisocyanate were added all at once to the reactor used in Example 1 and reacted at 220 ° C. for 20 minutes in a bulk, nitrogen atmosphere. After this, 2
The temperature was raised to 80 ° C., and the reaction was continued for 20 minutes. The inside of the system became viscous with the reaction. The produced polymer had a Vicat softening point of 124 ° C., a breaking strength of 480 kgf / cm ² and a breaking elongation of 450%. The resulting polyurethane had flexibility at room temperature.

Example 3 4,4 '''-dihydroxyethoxy-p-quarterphenyl 2
0.4 g (0.059 mol) of polyether (BAS
200 g of Company F (PolyTHF2000) is added to a reaction vessel equipped with a stirring blade, a material inlet, a nitrogen port or a decompression port, whose inside wall is made of glass and whose temperature can be controlled in a temperature range of room temperature to 300 ° C. 240 under nitrogen atmosphere
The reaction was carried out at 10 ° C. for 10 minutes. Thereafter, when the temperature was raised to 260 ° C., the inside of the system became transparent in one hour. 27.6 g (0.159 mol) of tolylene diisocyanate was added thereto, and the reaction was continued for 20 minutes. As the reaction progressed, a viscous milky white fluid was obtained. The generated polymer has a Vicat softening point of 108 ° C. and a breaking strength of 380 kgf / c.
m ² and elongation at break were 850%. The resulting polyurethane had flexibility at room temperature.

Example 4 16.9 g of 4,4 '''-dihydroxy-p-quarterphenyl
(0.05 mol) and bisphenol A (11.4 g)
(0.05 mol) and polyether (BASF; P
200 g of poly (THF2000) and 50.1 (0.2 mol) of diphenylmethane diisocyanate were added all at once to the reactor used in Example 3, and a reaction was carried out at 220 ° C. for 20 minutes in a bulk nitrogen atmosphere. After this 2
The temperature was raised to 80 ° C., and the reaction was continued for 20 minutes. The inside of the system became viscous with the reaction. The produced polymer had a Vicat softening point of 96 ° C., a breaking strength of 430 kgf / cm ² and a breaking elongation of 650%.

[0059]

As is apparent from the above description, according to the method for producing a thermoplastic polyurethane of the present invention, a thermoplastic polyurethane having rubber elasticity and excellent in heat resistance and mechanical strength is prepared by dissolving a solvent in a solvent. It can be manufactured without using. Therefore, the manufacturing process can be simplified, and it is advantageous in terms of energy and cost. The obtained polyurethane can be suitably used for various members as an excellent thermoplastic elastomer.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Daishiro Kishimoto 2-11-20 Mishimaoka, Ibaraki-shi, Osaka (56) References JP-A-3-115353 (JP, A) JP-A-2-502384 (JP) , A) Patent 2654342 (JP, B2) Patent 2694552 (JP, B2) Patent 2660442 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 18/00-18/87 CA ( STN) REGISTRY (STN)

Claims (1)

(57) [Claims] (1) at least one of a dihydroxy compound represented by the following general formula [I] and a monohydroxy compound represented by the following general formula [II], and (B) a polyether; , and (C) a diisocyanate, and a chain extender as needed (D), 20
A method for producing a thermoplastic polyurethane, characterized by performing a bulk reaction in a temperature range of 0 to 300 ° C.
Here, the amount of the dihydroxy compound [I] added was polyurethane.
1 to 30% by weight of the total monomers constituting the tan;
Method 1 (Wherein R ¹ and R ² independently represent an alkylene group;
p is 3 or 4, and q and r independently represent 0 or an integer of 1 or more). Embedded image (Wherein, R ³ represents an alkylene group, 1 is 2 or 3, and m represents 0 or an integer of 1 or more).